Top Family Soak: Goldbug Hot Springs, Idaho
High up a tumbling creek with yawning views of the Salmon River valley, Goldbug is perfect for a nature-loving family with big lungs. It’s a respectable hike from the Goldbug trailhead to this steamy terrace of semi-private pools tucked along a cascading creek–almost 1,000 vertical feet over three miles. But it’s worth it: The water is bathtub-warm, the surrounding hillsides are grassy and inviting, and when the kids are busy building slime castles, mom and dad can watch the sunset from one of the couple-size pools nearby. Salmon-Challis National Forest: (208) 756-5100; www.fs.fed.us/r4/sc. Guidebook: Hiking Hot Springs of the Pacific Northwest, by Evie Litton ($17; Falcon Press). Goldbug Hot Springs UTM: 12T 0268768E 4976571N

Best Underwater View: Midway Hot Pots, Utah
Bring your regulator and dive mask to this developed pool south of Salt Lake City for one of the only diveable soaks in North America. Managed by Homestead Resort, this surreal tub is housed in a 200-foot wide, 55-foot-high natural tower formed over hundreds of years by the minerals in the hot spring itself. If you’re not into underwater exploration, simply bob in the 90°F water. Novices can get certified here, and experienced divers can explore the depths (the tub is 65 feet deep) with a guide. Reservations are required for diving. The Homestead: (888) 327-7220; homesteadresort.com. Midway Hotpots UTM: 12T 0459761E 4485250N

Best View: Conundrum Hot Springs, Colorado
Located near the base of the 14,000-foot-high Maroon Bells, these pools are simply perfect–hence popular, especially during the summer. The quieter option? Ski in during early spring, when the snow tends to be stable (though slides are still a possibility). Strap on climbing skins and an avalanche beacon at the Conundrum Creek Trailhead (seven miles outside of Aspen on Castle Creek Road) and climb nine snowpacked miles to the 100°F pool. Pair ego-pumping corn-snow descents by day with joint-loosening dips in the steamy water by night. White River National Forest: (970) 925-3445; fs.usda.gov/whiteriver. Map: USGS Maroon Bells and Hayden Peak topos. Conundrum Hot Springs UTM: 13S 0336276E 4319809N

Most Remote: Red Hill Spring, ANWR, Alaska
In addition to polar bears and a 40,000-strong caribou herd, the Arctic National Wildlife Refuge also shelters the farthest-north hot spring in North America–and probably the most pristine. Only a handful of hardy travelers even make the trek this far north (just 10,500 recreational ANWR visitors last year). Be among the two or three of them who sojourn to Red Hill Springs, a cluster of tundra-ringed pools at the western end of the Sadlerochit Mountains, which overlook ANWR’s coastal plain. Air taxi is the only way into the Refuge, and then it’s a one- to two-day trek to the springs (depending upon where your pilot drops you). The roughly 90°F waters aren’t exactly steamy, but we guarantee you’ll be the only guy at the bar who can say he’s soaked on the 69th parallel under the midnight sun. Native Inupiaq guide and conservationist Robert Thompson leads trips to the Refuge (907-640-6119, kaktovikarcticadventures.com). ANWR: (800) 362-4546; arctic.fws.gov. Red HIll Hot Springs UTM: 6W 0537802E 7724579N

Desert Solitary: Goldstrike Hot Springs, Lake Mead NRA, Nevada
Sorry, Vegas: Nothing on the strip beats the party at Goldstrike Hot Springs. If you’re into deep, isolated canyons and bathtub-warm, emerald-green water, head about an hour south of Vegas and hike two challenging miles, scrambling over boulders up a slot canyon, to these 100°F pools. Fed by waterfalls that trickle down the canyon walls, they are also accessible via raft or kayak on the Colorado River. Lake Mead National Recreation Area: (702) 293-8906; npsgov/lame. Map: Boulder City topo. Gold Strike Hot Springs UTM: 11S 0702666E 3984683N

All-Natural Sauna: Pahoa Steam Caves, Keauohana Forest Reserve, Pahoa, Hawaii
Several hot springs bubble close by at Pohoiki Bay, but these unique natural steam saunas deep in the Big Island’s rainforest are well worth a visit–provided you’re not claustrophobic. Access the muddy, unofficial trailhead off HI 130 past Pahoa at mile marker 13, then scramble through exotic orchids and 6-foot-high ferns to the saunas. You’ll navigate the hip-high caves on hands and knees; some are shoulder-wide, and others require shimmying down a narrow vent or ladder into a cavern. Hawaii DLNR: (808) 974-4221; state.hi.us/dlnr. Pahoa Steam Caves UTM: 5Q 0335529E 2130780N